As a component of cell membranes in the living body, a sphingolipid contains a basic backbone of sphingoid long-chain bases such as spingosine, phytospingosine, and sphinganine. It was found that phytospingosine is generated in the skin by decomposition of ceramaid by ceramidases, and is present at a content of approximately 1 to 2% in the stratum corneum. The phytospingosine is known to serve to have an antibacterial effect on exogenous microbes, alleviate skin inflammations and heal wounds in the skin. Also, it was found that the phytospingosine penetrates deep into the skin, and is used as a precursor for synthesis of ceramaid to promote the synthesis of ceramaid, and conformed that the phytospingosine inhibits protein-kinase C or phospholipase D to alleviate inflammations. Accordingly, the phytospingosine is effective in alleviating skin diseases accompanied by chronic inflammations such as atopy. In particular, it has been reported that the phytospingosine has a high antibacterial activity against Staphylococcus aureus (S. aureus) as a microbe often found in the atopic dermatitis, and Propionibacterium acnes (P. acnes) as a pathogen causing acne, compared to the antibiotics such as penicillin or erythromycin, is safe as a natural ingredient without any side effects, and is also effective in promoting the synthesis of collagen and the generation of epidermal cells.
The phytospingosine was first extracted from a plant, but has been often found recently in marine life, especially in mammalian tissues, as well as microbes such as fungi, yeast, etc. The phytospingosine currently used was generally extracted from the yeast Pichai ciferrii. However, such phytospingosine has limits in use for cosmetic and pharmaceutical applications due to problems regarding insolubility in water. As a plan to solve the problem regarding the water solubility of phytospingosine, Korean Registered Patent No. 0343885 discloses a method of preparing a transparent aqueous solution, which includes adding lactic acid and a willow bark extract to water without using a solvent such as an alcohol and dissolving phytospingosine, and Korean Registered Patent No. 0690103 discloses a method of preparing an aqueous solution using liposomes having a size of 100 nm or less and containing a high concentration of phytospingosine. However, the phytospingosine still has problems in use due to occurrence of precipitates when stored for a long period of time or a high viscosity of formulations.
The present inventors have conducted research in various aspects to solve the above problems, and found that, when phytospingosine and maltose or lactose, which is an aldose-based disaccharide, are used to synthesize a phytospingosine derivative, the phytospingosine derivative has an excellent antibacterial effect while making up for the drawbacks regarding the water solubility of phytospingosine, and a composition including the phytospingosine derivative has a superior function in improving and preventing bacterial skin diseases, inflammatory skin diseases, and autoimmune diseases as well. Therefore, the present invention has been completed based on these facts.